The object of the present invention is a valve of reduced size intended to be fastened tightly in the rim of a wheel in order to assure the supply of air to a tubeless tire mounted on said rim, and more particularly a valve intended for heavy-vehicle tire rims of sheet steel.
The sheet-steel wheel rims of heavy vehicle tires, such as the rim shown in FIG. 1, conventionally have their region of assembly between the rim and the wheel disk located between the bead seat on the wheel-disk side and the wall of the mounting well. Preferably, this connecting zone is located in the immediate vicinity of the end of the bead seat. The valve hole is disposed in the outer wall of the mounting well of the rim. The valve stem is introduced into the valve hole from the radially outer side of the rim (corresponding to the inside of the tire after the mounting of the latter) and is locked by a nut screwed on from the inner side of the rim. The valve base is adjacent an annular recess which accommodates a sealing joint. Upon the locking, the nut is tightened to a given torque. The bent valve stem extends through an opening in the disk of the wheel. In this way, the valve stem represents a protuberance in the space located between the rim and the axle, in which space the hub and the brake members are housed.
On occasion, an untimely deflation of the tires occurs due to breakage of the valve. With axles provided with disk brakes, there is the possibility of passage between the bottom of the rim and the brake disk of foreign bodies which are carried along in rotation into these cavities and can become wedged, in particular, between the valve stem, which turns with the wheel, and the brake caliper which is stationary. The passage of foreign bodies into these cavities is facilitated by the free space between the rim and the brake disk. One then observes mechanical impacts caused by these foreign bodies wedged between movable and stationary parts. These impacts may be sufficiently severe to break metal parts, such as the valve stems or damage the rim or the parts constituting the brake caliper, and the braking system in general. This leads to critical situations, whether by failure of braking or by a sudden flattening, in addition to maintenance problems.
One solution consists in arranging the valve hole in such a manner that the valve stem is placed outside the cavity defined by the rim, the wheel disk, and the brake members. In other words, the valve hole extends to a zone located axially to the outside of the wheel disk. Such arrangements for the valve hole are conventional for wheels of passenger cars or for certain alloy cast wheels for utility vehicles, but have not yet been applied to the plate wheels of utility vehicles.
In fact, it has been observed that the application of the above solution to plate wheels for utility vehicles can result in a considerable decrease in the resistance to fatigue of the resultant wheels.
In order to obtain wheels of acceptable fatigue strength, the applicant has discovered that it was necessary to locate the region of assembly between the disk and the rim as close as possible to the end of the bead seat on the disk side. This solution considerably reduces the space available for the valve stem on the radially inner side of the rim and, in particular, the valves conventionally used can no longer be used since the valve stem cannot be bent at an angle sufficient to be able to be mounted on the rim while permitting the screwing-on of the nut.
A valve in which the stem is directed perpendicular to the axis of the valve hole is disclosed in U.S. Pat. No. 2,864,426. That valve is mounted in reverse manner. The valve base has a tubulure introduced through the valve hole from the radially inner side of the rim and locked by a nut screwed on from the outer side of the rim. The valve base has an annular recess intended to house a sealing joint and, in the case of a "toroidal sealing ring" (FIG. 1), a resting surface against the surface of the rim is also annular. In the case of a "grommet" (FIG. 3), the valve base does not have an annular resting surface but a simple protective collar for the joint. The valve base comprises a connecting chamber between the preceding tubulure and a perpendicularly arranged stem.
This solution has various drawbacks. The first relates to the fact that the locking nut is located completely on the outside of the rim. As a result, the mechanical connecting surface is reduced, which results in problems of mechanical strength or, if this length is increased, this means an extensive protrusion to the inside of the tire cavity, which may injure the heel of the tire upon its mounting.
Another problem relates to the transverse size of the valve, which is still too great; this valve therefore cannot solve the problem in question.